Method of producing fan hubs



Nov. 16, 1943. J. R. THORP 2,334,456

METHOD OF PRODUCING FAN HUBS Filed May 19, 1941 ATTORNEY.

Patented Nov. 16, 1943 31 aispnemenmyne; 1941; s enai nmeeeoea ii clw f io ri e-( 11a; I

Thisinventibn.relatesto improvements imfttfisg and is 'directed more particularly to improve merits in. the 'constru'etio'n' andioperation of fan assemblages having blades formed; o fpllabl :m'ater-ial such asrubberr 1 Anobject of: the; invention i's tb pmvide an improved method of produ'oing ovoidifan hub's on the like; from: sheet metal oifs'imilai material:

Rubber bladed fan's, wherein two: ormore blades. formed; ofirelativelyfi soft andpliablerub ber adapted. to deflect umn: striking an "ex traneous. object during; rapid: revolutionoi: the fan rotor are utilized, have become: quite popu lar'. for various. aiir .cirouIatin'g; purposes? In constructing fans of: this: type,. itz hak's heretofore been. common. practice to; provide-mach rubber blade. with an: enlarged: inner end or: baseaportion' adapteditmbeinsertedwithin-aspiral helieal slot. formed; in a: metal ovoidzones-haped -huh; and: to firmly'se'cure the hub imsome' mama to' thefansupporting shaft of the prope'lhirg nde tor. In small fan assemblages, the blad sup porting. hubs were usuallyformed; as dieeaast ingswrequiringrather expensive equi iiiiieinri in? theirfor'mation', and also necessitti' g th use 25 oij specialimetal' whioh is} rather costly and dfficult' t'o obtain, '1 h'e usi oi th'eeeFdie GaStings was-"however advantageous neeause t obviated difficulties in producing' prcper i shape era the spiral-h elical blade receivingslbts 'formedQin-BO the ovoid hubs, whieh slots oeiifidhot; hert' 1 fore be rea'dilyformed -'ihsheet met'al hub' a sembl'agea without the aid oi eomplicated and expensive dies; i

It is therefore anv object ofi iny present) livery 313 movement which may obviously beapplied to.

tion t6 providean improved method 0? fer-mingthe -slbtted l hubs for rubber L bladed fans: on the like, of relatively inexpensive materiai smdj with the aid of comparatively simple'eqifiiiment i Another specific object? of tlie present"inveIi i-' 40 tion is" to provide an improved meae'or lirocl 'iee ing sheet metal ovoid-shaped f'a-ni hubs provided With" two orinore spiral helica-l blade receiving andretaining 'slots. r

A further specific object of my invent-Flor13is to'--45 provide a method of-' manage new andFiiseful fan hubassembly which can 5e-radily1con'-- struct'ed, assembl'ed'andf dismantled? and infwliich the bl-ades are easily ihsertibl'" and firmly re tained; I l U Still another specific" objector theinve ntiorr is to provide a method of making an improvert fan hub structure formed of relativelv iew durable parts, and whichpreseme anew-ana attractive appearanee when finalfi assemblerfi *An additional specifie object-- of this= invention isto provideamethod of maleing asthrdyd'ynar'n ical1y= balanced sheet; metal fan; hub, which can be positively attached to: a* driving shaft; and whibh may also be produced relatively small;

si-ze's and at moderate cost.f

' These and= other speeifie objects and advantages will be apparenfi'from'the following'detaileddesbription. v. l 1

A clear conception -of the se'veral features constituting the present improvement; and ofthemode' of. constructing and of assembling fan rotors built" inaccordance with the invention may be. had; byreferring to thedrawing accompany 1 ing. and. forming rampart; of" thisspecification wherein like". reference characters; designate the.

same or: similauparts'inthe various views;

Fig. 1. is; a; plan. view of. ones of 1 the? improved sheeiiimetal blanksused informing. theahub ofa threeibladefan;

Fig. 2 is an enlarged longitudinal section through; a-ltwo blade fanhubi assembly embodying the i invention. showing; fragments only of. the,

bladesandoi the propellingimotorg, l

Fig-L13. is a reduced. front; elevation of; the; two blade; fan; assemblage; portions having been.

broken away to show the. blade attachment}. and Fig, L is; a transverse: section; through, the. in?

V neroribase-portion of one of the? rubber blades.

While: the-invention has been. shown andde= scribed herein. as being specifically; embodied in rubber; bladed, fans having semi-ovoid; hubs adapted; to support; either two or, three: flexible.

.. blades,-;it is not desired to therebmunnec'essarily limit or restrict: the scope :1 or-utility; of the imfans having more than threebladesr T-heimproved fan hub assemblagemay be used in fans having two orrmore individuaLblades,

and; aslill ustratedinrlifig s. 2 and 3-,: this; assem blage; comprises.- a semi-ovoid shapedihub mem ber. .6..pr.ovided .withtwo or more spiralehelical blademebeivingf slots, 1 theouter. ends oiiwhich lj andj being provided witha projection. l5 extendingithrough the adjacent openingS; a central supporting 'sleeve lirigidlg; attached at one 55' end IT to the centerof'the plate l0; and'having its opposite end provided with a threaded socket I8; a set screw I9 for positively securing the sleeve I6 to a driving shaft 20 coacting with the bore of the sleeve I6; a front nose cap 2| adapted to coact with the hub member 6 adjacent to the open ends of the slots 1, and to also engage the blade projections I and a clamping screw 22 coacting with the cap 2I and with the sleeve socket I8, to clamp the hub in assembled condition.

The hub member 6, the closure plate I6, and

the clamping cap 2| may all be formed of sheetmetal with the aid of punches and dies, and the r formation of the semi-ovoid hub member 6 of sheet metal, constitutes an important feature of the present invention. As shown in Fig. 1, the member 6 may be produced from a fiat blank of sheet metal formed symmetrical with respect to i 'a central axis, and having a series of equally spaced radiating spiral sector shaped cut-outs 23 separated by similar intervening lobes 24 The inner ends of the cut-outs '2 3 terminate in then v r o i s 9, n t e cor e n outer portions of the lobes 24 have integrallateral projections '26,; while the. center gf the blanlg is provided with a circularhole 21 The blank-;is-of uc shape, t a f en w t s dist ted, nt th desired semi-ovoid shape with the aid of suitable dies, the adjacent side edges of the succes s ive lobes, 24 will form-the parallel sidedblade receiving slots I, and the'projections26 will belocatejd atrthe splits 8 thus producingslots-of proper and;

uniform width. The outeriperipheraledge l2 of the formed blank will lie in, a common, plane perpendicular to the hub axis and will be ready for. snug dispositionv Within the ring wgroovel I, while the inner ends-of thebladejconfining'slots 'I will beopen by virtue of the inward 'dishingpfthe central portion 28 of the blank so as to position the openings 9 in planes perpendicular vtoethe slots-I.

The end closure plate .It may. likewise" he formed of a single sheet of metal with the aid of punches and dies, and as previously indicated, the annular recess or groove II isshaped 'to snugly engage the end or outer edge I2 of the member 6.

The closure plate lil may be dished inwardly as shown inFig. 2, in'order to stiffen the same and the mountingsleeve I 6 may be rigidlyattached to the plate 56 at the sleeve end l'l byriveting welding, or otherwise. The opposite end-of-the sleeve I6 adjacent to the'threaded socket-I8 may be tapered as shown in order to guide the clamping;

screw: 22 and to prevent direct coaction between-Q the nose cap 2| and'the'sleeve I6; and the st F screw I9 which is carriedby and-penetrates th supporting sleeve, coacts with a flattened portipfn 29 on the driving shaft 2t so'as topositively prevent the hub fromrotating on 'thefsha'ft "Iih i shaft may be driven by an electric'motor 36 or other mwer means aniline ope .or hole 2'l formed in" the central hub portion-T23, is adapted to's'nuglyfit the reduced fronttportionf of ithe sleeve" I6 and to coact witha shoulder 3 l thereon. The nose cap 2| which may -also be;

sheetmet'alwith the aid of'punc hes and diesgis adapted to snugly 'engage the hub member 6 adjacent to the transverse openings 9; tothereby close the forward or inner ends of the slots" 'I, and the periphery of this cap 2I is, also adapted to snugly engage all ofthe bladeprojections' l5. The blades I3 may beiformedl of pliable material such" as soft rubber, and the base portions I4 thereof are preferablyenlargeda's shown in Fig. 4,

ed of and are provided with side grooves 32 adapted to coact with the adjacent side edges of the lobes 24.

When the various elements of one of the im-' sleeve I6 to the shaft 20. The several flexible blades- B may then be inserted within the spiral-'- helical slots l of thehub member 6, with the bladeenlargements orbase portions I8 disposed within thi's' member, and the projections l5 extending forwardly and outwardly of the slots I through the openings 9. The blade and hub member, assembly may then he slipped over the forwardend of the sleeve l6 and the peripheral edge portion I2 of the hub member 6 may be caused to enter the groove ll of the closure plate I9. As a final step in the assemblingoperation,

the front nose cap 2 I- may be applied to the blade projections I5 and the clamping'screw 22 may be driven home, thereby notonlyforcing the cap 2| against the projections; I5, but also driving the,

hubmember '6 into the-continuous groove I] of theplate. I 0. The fan assemblage may thereafter be operated without danger of having the parts become loose, and since the structure is I dynamically balanced, smooth rotation of the fan will alwaysresult.

From the foregoing detailed descriptiomit will be apparent; that my present invention not only provides an improved fan hubassemblage which is simple,ilight and-durable in construction, but also-provides a new and usefulmethod of producing and of assembling the fan structures. The various, elements-bf the assemblage can be readily produced at moderatefcost,.,with the .aid of simple machinery suchas, punches, dies and screw machines, and the entire hub structure isefiec tively; clamped and-retained in assembled condition with the aid of but a single assembly screw.

Theimproved hub assemblage may bepositively locked to thesupporting and driving shaft by means of a; single setscrew which is normally concealed within the hub, and the formation of '1 the slots 1 in the semi-ovoidhub member 6 facilitates application of theblades-to the hub and insures firm retention thereof in proper position without permittingcreeping of the blade bases along these slots. Thenose cap at the forward end of the hub assemblage, performsthe dual function, of locking: the blades in-placeand of clamping the plate It} and the cap against the opposite ends of the hub member 6, and the axial clampingscrew can be readily manipulated to effect rapid assembly and dismantling of the structure; ,By virtue of the improved formation of the hubmember 6, the blade receiving slots '1 may be accurately produced with smooth opposite side edges which will not interfere with free introducon hebla r It shouldbeunderstood that it'is not desired to limit the invention to-the exact details of construction, or to the precise mode of forming the hub structures, hereinshown and described, for

various modifications within the scope of the claims ay occur to personsskilledin th art.

.I claim:

1 The method ofproducing an ovoid fan-hub, i h h ,i m e f rm n a :ila 'shcetr'material blank symmetricalwith respect to a central axis:

and having spiral sector shaped cut-outs each provided with a transverse terminal opening at the extreme inner end thereof nearest said axis, dishing the central portion of the blank to cause said openings to lie in a frusto-conical annulus and to assume similar angular positions with respect to the plane central portion of the blank, and reversely dishing the spiral lobes of the blank between said cut-outs into semi-ovoid shape to provide spiral-helical blade receiving lots at the cut-outs the inner ends of which terminate at the corresponding openings and are directed approximately perpendicular to the planes of the adjoining openings.

2. The method of producing an ovoid fan hub, which comprises, forming a flat sheet-material blank symmetrical with respect to a central axis and having outwardly extending spiral lobes each provided with a lateral outer projection and adjacent lobes being separated by spiral sector shaped cut-outs each provided with a transverse terminal opening at the extreme inner end thereof nearest said axis, dishing the central portion of the blank to cause said openings to lie in a frusto-conical annulus and to assume similar angular positions with respect to the plane central portion of the blank, and reversely dishing the spiral lobes of the blank into semi-ovoid shape to cause said cut-outs to contract into spiralhelical blade receiving slot formations the widths of which are determined by engagement of said projections with the adjacent lobes and the inner ends of which terminate at the corresponding openings and are directed approximately perpendicular to the planes of the adjoining openings.

3. The method of producing an ovoid fan hub, which comprises, forming a flat sheet-material blank having spiral lobes radiating from a central axis and separated by spiral sector shaped cutouts the inner end of each of which terminates in a transverse opening, dishing the central portion of the blank in one direction to cause all of said openings to lie in a frusto-conical annulus and to assume similar angular positions with respect to the original plane central portion of the blank, and dishing the lobes in the opposite direction to contract said cut-outs into spiral-helical slots the inner end of each of which terminates in one of said openings and is directed approximately perpendicular to the plane of the adjoining opening.

4. The method of producing an ovoid fan hub, which comprises, forming a flat sheet-material blank having spiral lobes radiating from a central axis each provided with a lateral outer projection and being separated by spiral sector shaped cut-outs the inner end of each of which terminates in a transverse opening, dishing the central portion of the blank in one direction to cause all of said openings to lie in a frusto-conical annulus and to assume similar angular positions with respect to the original plane central portion of the blank, and dishing the lobes in the opposite direction to contract said cut-outs into spiral-helical slots of uniform transverse width as determined by engagement of said projections with the adjacent lobes and the inner end of each of which terminates in one of said openings and is directed approximately perpendicular to the plane of the adjoining opening.

5. The method of producing an ovoid fan hub, which comprises, forming a flat sheet-material blank having spiral lobes radiating from a central axis each provided with a lateral outer projection and being separated by spiral sector shaped cut-outs the inner end of each of which terminates in a transverse opening, dishing the central portion of the blank in one direction to cause all of said openings to lie in a frusto-conical annulus and to assume similar angular positions with respect to the original plane central portion of the blank, dishing the lobes in the 0pposite direction to contract said cut-outs into spiral-helical slots of uniform transverse width as determined by engagement of said projections with the adjacent lobes and the inner end of each of which terminates in one of said openings and is directed approximately perpendicular to the plane of the adjoining opening, and confining the outer lobe ends and said projections in a solid ring.

JOEL R. THORP. 

